The present invention relates to a magnetic film and a magnetic head using the same, and more particularly to a magnetic film for the magnetic pole of a magnetic head and a magnetic head using the same, particularly suitable for high density magnetic recording.
As a material for a magnetic pole of a magnetic head for high density magnetic recording, an alloy whose main component is Fe, Co and Ni and whose saturation magnetic flux density is no less than 10 KG, and an Fe-Si alloy having a saturation magnetic flux density no less than 18 KG have been developed (JP-A-59-182938). It is necessary for the tip of a magnetic pole of a magnetic head to have a thickness no larger than 0.5 micron if high density magnetic recording is intended, which requires a steeply distributed magnetic field of the magnetic pole. Since the magnetic flux density at the tip becomes high, a magnetic film with high saturation magnetic flux density, high permeability and low coercivity becomes necessary. In addition, since the film thickness at the tip is small, magnetic saturation may occur. Thus, for a film thickness no larger than 0.5 micron, a high saturation magnetic flux density no less than 15 KG, high relative permeability no less than 1000 and low coercivity no larger than 1 Oe become necessary.
A magnetic film has been formed by the RF sputtering method or the like. The magnetic characteristic of a magnetic film containing Fe as its main component exhibits a high saturation magnetic flux density no less than 15 KG. However, its relative permeability exhibits a low value no larger than 700. Thus, it has been difficult to form a magnetic film having both high saturation magnetic flux and high relative permeability.
Recently, as a magnetic film having high saturation magnetic flux density and high relative permeability, a multilayered magnetic film with magnetic films laminated between intermediate layers has been studied (JP-A-59-9905). The magnetic characteristic of a multilayered magnetic film changes depending upon the material of intermediate layers between main magnetic films. Generally, it is preferable to use magnetic material having high permeability.
According to a prior art technique, a magnetic film for the pole of a magnetic head is formed by the RF sputtering method or the like. Such a magnetic film has a fairly high saturation magnetic flux density, but its relative permeability is low. Thus, it cannot be used as a magnetic film for a magnetic head for high density magnetic recording.